Incandescent electric lamp



June 12, 1928. 1,673,267

R. A. PRICE INCANDESCENT ELECTRIC LAMP Filed May 15, 1924 [221/92123)" BaZoZzfiZPabe Patented June '12, 1928.

UNITED STATES 1,673,267 PATENT OFFICE.

RALPH ARTHUR PRICE, OF BERWYN, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

INCANDIESCENT ELECTRIC LAMP.

, Application filed May 15,

This invention relates to an incandescent electric lamp, and more particularly to means for supporting the filament thereof.

In an electric lamp of one form, such as that employed in telephone switchboards or the like, the lamp-bulb comprises a glass cap and a glass stem, the glass stem being Welded to the cap and being adapted to project into the cap. The inner end of the stem 15 formed with annular flanges in which are embedded a plurality of mount wires sup porting a filament, the mount wires being directly connected to the leading-in wires of the lamp. In order to embed the mount wires in the annular flange of the glass stem, it is necessary to draw or force them into the glass when it is in a fused state.

An object of the invention is to facilitate and to cheapen the manufacture of an electric lamp having metallic means for supporting the filament thereof.

Another object of the invention is to mount the filament of an electric lamp by an inexpensive means which is chemically inactive in comparison With base metals.

A preferred form of the invention is embodied in an electric lamp wherein the filament is supported by a plurality of mount wires, each of which comprises an alloy of seventy per cent of gold and thirty per cent of silver.

Other objects of the invention will become apparent as the detail description progresses, reference being had to the accompany ng drawing wherein,

Fig. 1 is a central longitudinal section through an electric lamp embodying the invention;

a Fig. 2 is an elevation of the lamp shown in Fig. 1;

Fig. 3- is a section taken on line 33 of Fig. 1,'and

Figs. 4 and 5 arc-views illustratin rious stages in the manufacture o lamp. I

Referring for the present to Figs. 1, 2, and 3 wherein an electric lamp embodying one form of the invention is shown, the reference character 10 designates generally the lamp-bulb of the lamp. This bulb 10 comprises a cap 11, and a tubular glass stem 12 which projects upwardly into the cap 11 and is welded to the lower end thereof as indicated at 13. The upper end of the stem 12 is provided with. an annular flange vathe 1924. Serial No. 713,461.

pecially adapted for use in telephone switchboards or the like, and closely resembles the signal lamp for telephone switchboards disclosed in U. S. Letters Patent 709,996 to F. R. McBerty and F. H. Loveridge of September 20, 19,02. However, it will be noted that the lamp described in that patent has its filament mounted directly upon a plu rality of platinum leading-in wires.

In the lamp shown in the accompanying drawing, each of the mount wires; 15 comprises an alloy of of gold and 30% of silver. As the advantages of this construction are best understood from a description of the methods employed in the manufacture of the lamp, a brief description thereof will be given. In substantial accordance with the method disclosed in U. S. Letters Patent 709,996, the filament of the lamp is-first assembled with the glass stem 12 to form a unit, which is inserted into the cap 11 and welded thereto in such manner that the leading-in wires 17-17 are sealed in the weld. While it is practical to employ leading-in wires of sufficient length to mountthe filament directly thereto, it is of course understood that this construction adds to the cost of roduction and that for this reason it is esirable to dispose mount wires of a cheaper metal or metals between the leading-in wire and the filament. It is impractical to employ the base metals for this purpose, as the base metals are chemically active and tend to enter into chemical reactions which result in a lowering of the efliciency of the lamp. Therefore, it'is preferable that the mount wires comprise chemically inactive materials and that these wires have properties which are adapted to meet the conditions met with in the manufacture of the lamp. Thus the metal or metals of which the mount wires are made must be able to withstand a relatively high degree of heat. In the manufacture of the lamp, the mount wires first form a single length of Wire, the two ends of which are welded to the leadingin wires 17; Then the integral mount wires 15 are brought into the position with respect to the glass stem 12, wherein they are shown in Fig. 4, and theannular flange 14 of the stem is heated by a gas flame until the glass issufficiently fiuid to permit the mount wires to be drawn or forced into the glass. The mount wires are then severed from each other and the. upper ends thereof are brought into the positions indicated by dotted lines in Fig. 4. After the filament 16 has been accurately positioned upon and secured to the mount wires 15, the cap 11 is correctly positioned with respect to the glass stem 12 and welded thereto.

As hereinbefore set forth the mount wires employed in the preferred embodiment of the invention are made of an alloy comprising gold and silver. The gold gives the alloy a: relatively high melting point and the silver insures that the mount wires will be sufficiently rigid to hold the filament in its correct position within the lamp-bulb. The addition of silver also cheapens the mount wire. The alloy preferably employed comprises substantially 70% of gold and of silver, as this alloy has amelting point approximating the melting point of gold.

I If the proportions of the alloy are varied so that it comprises a larger percentage of gold, the melting point of the alloy will continue to approximate the melting point of gold, but the cost of the alloy will be increased and the rigidity of mount wires made thereof will be lessened. However, it is not. desirable to vary the proportions of the alloy so that it will contain a smaller percentage of gold, as the melting point of the alloy is lowered proportionately when the silver content. thereof is more than 30%. Of course, the addition of silver to the gold aids in the Welding operation by which the mount wires are joined to the leading-in wires.

It is apparent that this invention facilitates and-cheapens the manufacture of an electric lamp wherein metallic means is employed to mount the filament thereof, as by the use of an alloy of the metals and the proportions set forth above, mount wires of small diameter may be employed which will be comparatively inexpensive. Another advantage is that the, mount wires may be welded to the platinum leading-in wires quickly and easily.

What isclaimed is:

1. In an electric lamp, a filament, a support of insulating material, and means cooperating with thesupport. to position the filament, the means comprising an alloy hav' ing more than of gold and more than 10% of silver as constituents thereof.

2. In anelectric lamp, a filament, and a mount wire for the filament comprising an alloy including more than 25% of gold and including more than 5% of silver- 3. In an electric lamp, a filament, and a conductor supporting the filament, said conductor comprising an alloy of gold and silver, having more than 50% of gold and halvling a higher degree of rigidity than go 4. In an electric lamp, :1 filament, a support of insulating material, and means cooperating with the supportto position the filament, the means comprising an alloy of gold and silver with the percentage of gold predominating.

- 5. In an electric lamp, a filament, and a mount wire for the filament having electrical conductivity properties comprising an alloy of gold and silver with the percentage of gold predominating.

In witness whereof, I hereunto subscribe my name this 31st day of March, A. D., 1924.

RALPH ARTHUR PRICE. 

